@scott schmerge and
@avslash I did mine and it's worth it. After doing so, I placed an oil catch cans on each bank. To my surprise, bank 2 doesn't need it. Bank 1 on the other hand sucks a LOT of air from the intake manifold. The vacuum is ridiculous in bank 1.
I haven't measured it, but I've used 5/8" ID (Inner Diameter) black rubber HD fuel lines and the lines collapsed under vacuum. Then I used clear reinforced vinyl tubing with 5/8" straight through barb connectors just to see what happens. I drove about 20 miles with the heat and vacuum separating the inner hose with oil running through. In the meantime, I've put the stock pipe back on. I'm prepping up to build my own oil catch can out of aluminum that runs along the top RH side of the intake manifold. I've also ordered special 5/8" ID 11/16" OD PTFE tubing to handle the job. It has a higher tolerance to cold (-454* F) and heat (500* F).
Once I get the catch can done, I'll redo the walnut blasting.
First off get the proper tools, media blaster (gravity or siphon), fine walnut media, shop vac, extraction adapter, and blasting wand.
Siphon blaster:
https://www.amazon.com/gp/product/B0007D30DO/ref=oh_aui_search_asin_title?ie=UTF8&psc=1
Walnut media:
https://www.harborfreight.com/25-lbs-fine-grade-walnut-shell-blast-media-92155.html
Extraction adapter:
https://www.ecstuning.com/b-genuine-mini-parts/extraction-adapter/81292208038/
Blasting wand:
https://www.ecstuning.com/b-genuine-mini-parts/strahlsonde-mini/81292208032/
To do it right, remove the ignition coils, spark plugs, fan cowl, fan, throttle body (without removing any connecting tubes), and completely removing the intake manifold. Put the truck in Neutral, choke the wheels, and put on the ebrake. Put a dowel rod (I used a long skewer stick) into each spark plug hole to find the highest point of the piston to ensure the intake valves are completely sealed. Tape off ALL valves, except for the one you're working on. Then start walnut blasting it until it's clean and air blast it clean. Don't use any chemicals in there. I'm just not sure if it'll cause any damage, but I wouldn't use it. Rotate the engine crank clockwise till you find the next valve to work on.
The cheat way, remove the fan cowl, fan, throttle body from the intake manifold and completely remove the intake manifold. There should be only 1 or 2 valves visually open, don't blast it. Tape off ALL valves and blast each one until those are done. Rotate the crank clockwise until the remaining 2 valves are in the closed position.
I recommend doing it correctly, it's only an hour longer to pull those plugs and it'll give you a sense of accomplishment. I think the total time with beer breaks was about 3-4 hours. I spent about 5-10 minutes per valve and that right there is already 40-80 minutes for all 8 valves.